The applications of touch input devices are very extensive. In the early stage, a touch input device is installed on a notebook computer. By operating the touch input device, the movement of a cursor may be controlled or a corresponding icon of a user interface may be clicked without the need of using a mouse to operate the notebook computer. With the advance of science and technology, a physical button may be integrated into the touch input device, so that the touch input device has a button function. Under this circumstance, it is not necessary to install plural physical buttons on the peripheral area of the touch input device. Since the physical button is integrated into the touch input device, the layout space is saved and the outward appearance is aesthetically-pleasing. Moreover, since the physical button is not installed in the touch input device, the button function can be easily implemented by simply depressing the touch input device. However, since the physical button is integrated into the touch input device, the possibility of erroneously implementing the button function will be increased during the process of operating the touch input device.
For solving the problem of erroneously implementing the button function, a conventional touch input device with a button function has been introduced into the market. Hereinafter, the structure of a touch input device with a button function will be illustrated with reference to FIGS. 1 and 2. FIG. 1 schematically illustrates a conventional touch input device with a button function. FIG. 2 is a schematic side view illustrating the touch input device of FIG. 1, in which the touch input device is depressed. Please refer to FIGS. 1 and 2. The touch input device 1 is in communication with a computer system (not shown). By operating the touch input device 1, the movement of a cursor (not shown) of the computer system may be controlled or a corresponding icon (not shown) of the computer system may be clicked. The conventional touch input device 1 comprises a casing 10, a touch plate 11, a supporting element 12, and two triggering switches 13. The touch plate 11 is disposed within the casing 10. Moreover, the touch plate 11 has a cursor control zone 111 and two button function zones 112. These two button function zones 112 are located at a lower left corner and a lower right corner of the touch plate 11, respectively. In other words, the cursor control zone 111 and the two button function zones 112 are not overlapped with each other. The two triggering switches 13 are respectively aligned with the two button function zones 112 and disposed under the two button function zones 112. The two triggering switches 13 are electrically connected with the touch plate 11. The supporting element 12 is connected to a sidewall of the touch plate 11 for supporting the touch plate 11 thereon.
For moving the cursor of the computer system, the user's finger is firstly placed on the cursor control zone 111 of the touch plate 11 and then the user's finger is moved on the cursor control zone 111, so that the cursor is correspondingly moved with the motion of the user's finger. On the other hand, the two triggering switches 13 are used as a left button and a right button, respectively. Since the cursor control zone 111 and the two button function zones 112 are not overlapped with each other, when the user's finger is moved on the touch plate 11, the possibility of erroneously triggering the triggering switches 13 by the user's finger will be minimized.
Moreover, the two triggering switches 13 of the touch input device 1 are separately triggered. For triggering one of the two triggering switches 13, the button function zone 112 of the touch plate 11 corresponding to the triggering switch 13 should be depressed in response to a strong downward force. Consequently, the touch plate 11 is subjected to deformation to push the triggering switch 13 (see FIG. 2). Under this circumstance, the triggering switch 13 is triggered to generate a button signal, and thus a corresponding button function is executed.
However, after the touch plate 11 has been used for a long time, the frequent deformation and recovery may damage the touch plate 11. If the touch plate 11 is damaged, the touch sensitivity of the touch plate 11 is deteriorated, the tactile feel of operating the touch plate 11 is impaired, and the use life of the touch plate 11 is shortened.
Therefore, there is a need of providing a touch input device with a button function in order to provide an enhanced tactile feel.